Bi-ionic actuator by polypyrrole films

Abstract

A new mechanism for driving the bimorph actuator using polypyrrole (PPy) films has been proposed. This actuator is consisted of two different PPy layers, in which one is electrochemomechanically deformed by the cation insertion and the other is deformed by the anion insertion. The freestanding deformation of each layer is opposite at a certain electrochemical potential with each other. Both deformations, however, cooperate to bend the film into the same direction by forming the bimorph structure. Since synchronized anion insertion and cation deinsertion drive this actuator, it can be expressed as a bi-ionic actuator (BIA). BIA offers its superiority over the conventional one having: (I) the double-active layers for the actuation, (II) the strong adhesive interface by inter-penetrating polymer networking and (III) the available technique for mapping two oppositely bending BIA units into the same film. The bending performance with double-active layer was compared to that with the single-active layer of BIA. The fabrication dependence and the folding performance were also investigated.